Lake Shore Model 480 Fluxmeter User’s Manual
5-6
Advanced Operation
5.4 MAKING MEASUREMENTS IN PERCENT
For applications where an absolute measurement in magnetic units is not required the Model 480 offers
the units of percent. This is intended to be a relative measurement for sorting operations or comparing
values. As an example assume a sorting criteria is given as ±10% deviation from a standard magnet.
The standard magnet can be measured with the Model 480. Its measurement scaled to a 100% reading
on the display. Magnets measuring between 90% and 110% pass and others fail. The percent scale
factor is the coil parameter used to scale a percent measurement. It is the only coil parameter that can
be changed on a Lake Shore probe.
5.4.1 Before Using Set Percent
The set percent feature can be used to calculate a percent scale factor. The feature can be initiated
with the instrument set to any measurement units but if the coil is uncalibrated, it is recommended
that the sequence be started with the units set to V·s. Several measurements of the test magnet
should be made to assure repeatability. An improper range setting or excess drift can cause difficulty
in repeating measurements.
5.4.2 Set Percent (%)
Begin the set percent sequence by resetting the reading with the
Reading Reset
key or the peak
hold value with the
Peak Reset
key. Make a measurement of the sample magnet or place the coil in
a known magnetic environment. Press the
Set Percent
key. The
Enter Percentage
screen will
appear on the display.
EnterPercentage
100.000_%
Use the keypad to enter the percent value that is to be assigned to the measurement (often 100% but
it can be different), then press the
Enter
key. The cursor will jump to a space before “
%
”. Use the
or
keys to select prefix µ, m, _, k, or, M. Press the
Enter
key to accept the change or the
Escape
key
to cancel the entry and return the previous value. The instrument will begin displaying in percent. The
sequence is successful if the display reading matches the value entered.
5.4.3 Percent Scale Factor
The percent scale factor can be viewed or entered directly. This feature allows the coil to be used
again with the same scale factor or transferred from one instrument to another. The scale factor is in
the empirical units of %/V·s.
To view or change the percent scale factor, press and hold the
Set Percent
key for 5 seconds.
PercentScaleFactor
200.000_%/Vs
Use the numeric keypad to enter the Percent Scale Factor in %/V·s, then press the
Enter
key. The
cursor will jump to a space before the “
%
”. Use the
or
keys to select prefix µ, m, _, k, or, M.
Press the
Enter
key, then the
Escape
key.